therascreen FGFR RGQ RT-PCR Kit

The therascreen FGFR RGQ RT-PCR Kit is a qualitative in vitro diagnostic test for the detection of two point mutations in exon 7 [p.R248C (c.742C>T), p.S249C (c.746C>G)], two point mutations in exon 10 [p.G370C (c.1108G>T) and p.Y373C (c.1118A>G)] and two fusions (FGFR3-TACC3v1 and FGFR3-TACC3v3) in the FGFR3 gene.

The therascreen FGFR RGQ RT-PCR Kit is a companion diagnostic (CDx) test for the identification of patients with cases of urothelial cancer (UC) that harbor these actionable FGFR alterations, and for whom treatment with BALVERSA (erdafitinib) is indicated.

The 42756493-BLC3001 trial was a Phase 3 study to demonstrate superiority of single agent BALVERSA (erdafitinib) over established (chemotherapy) and emerging (anti PDL-1/PD-L1 monoclonal antibodies) standard of care options in relapsed/refractory subjects with selected FGFR alterations (1).

During the Phase 3 study, BALVERSA (erdafitinib) was compared to vinflunine or docetaxel (cohort 1) or pembrolizumab (cohort 2) in subjects with advanced urothelial cancer and selected FGFR gene mutations. The primary endpoint of overall survival (OS) was evaluated in two cohorts:

• Cohort 1: BALVERSA (erdafitinib) versus chemotherapy (docetaxel or vinflunine) in subjects who have received prior anti-PD-(L)1 agent
• Cohort 2: BALVERSA (erdafitinib) versus pembrolizumab in subjects who have not received prior anti-PD-(L)1 agent

This study was conducted using the therascreen FGFR RGQ RT-PCR Kit as a CDx to screen patients for an FGFR mutation. Only cohort 1 was used for registration purposes.

For all observed FGFR mutation-positive (FGFR+) subjects in cohort 1, the primary efficacy endpoint of OS showed a statistically significant improvement in OS for subjects treated with BALVERSA (erdafitinib) vs chemotherapy (HR = 0.628; 95% CI: 0.438, 0.900; p = 0.0106). This represents a 37.2% reduction in the risk of death for subjects in the BALVERSA (erdafitinib) treatment group vs. the chemotherapy treatment group. In the erdafitinib group, the median OS was 10.94 months (95% CI: 10.12, 16.76). In the chemotherapy group, the median OS was 7.72 months (95% CI: 6.54, 11.30) (Table 1). These results demonstrated comparable efficacy with the drug intention to treat (ITT) population (HR=0.64; 95% CI: 0.47, 0.88; refer to drug labeling).

* p value is from a log-rank test.

^† Hazard ratio is from unstratified proportional hazards model. Hazard ratio <1 favors erdafitinib.

^‡ Censored observation.

NE: Not estimable.

The therascreen FGFR RGQ RT-PCR Kit is based on the selective amplification of alterations in the FGFR3 gene using the Rotor-Gene Q MDx (US) instrument for sensitive and specific analysis. The assay exploits the qPCR oligonucleotide hydrolysis principle using TaqMan probes.

Allele-specific technology allows accurate and highly reproducible detection of alterations, based on the use of specific forward and reverse primers and probes; only a perfect match between the primers and probes with the target cDNA allows extension and amplification in the PCR reaction. Result reporting is fully automated. If both the positive and no template controls are valid and the sample internal controls are valid, the FGFR alteration status will be displayed in the software

The fast and simple workflow takes ~12 hours from Sample to Insight.

RNA is first prepared from formalin-fixed paraffin-embedded (FFPE) urothelial tumor samples using the RNeasy DSP FFPE Kit. Purified RNA is then reverse transcribed using Reverse Transcriptase to generate cDNA for real-time PCR analysis. Optimized reverse transcription reagents and PCR master mixes provided in the kit enable high-fidelity reverse transcription and sensitive real-time PCR on the Rotor-Gene Q MDx (US) instrument. Qualitative results are displayed in Rotor-Gene AssayManager software, informing the system operator if one or more of the four point mutations and two fusions in the FGFR3 gene detected by the kit are present in each sample.

The therascreen FGFR RGQ RT-PCR Kit is also designed to identify FGFR2 fusions FGFR2-BICC1 and FGFR2-CASP7 and FGFR3 fusion FGFR3-BAIAP2L1, because patients harboring these FGFR fusions were eligible for the BLC3001 clinical trial. However, the test is not clinically validated to detect these three fusions. Drug safety and efficacy has not been established for cases of UC harboring these fusions and no claims are made for the use of the therascreen FGFR RGQ RT-PCR Kit as an aid in the selection of such patients for treatment with BALVERSA (erdafitinib).

The therascreen FGFR RGQ RT-PCR Kit enables qualitative detection of four point mutations and two fusions of the FGFR3 gene for in vitro diagnostic use. It is an approved CDx assay for the selection of patients with cases of urothelial cancer (UC) harboring actionable alterations, for whom treatment with BALVERSA (erdafitinib) is indicated.

1. therascreen FGFR RGQ RT-PCR Kit Instructions for Use. January 2026